# range语法1：range(num)
# for x in range(10):
#    print(x)

# range语法2：range(num1,num2)
# for x in range(2,10):
#     print(x)

# range语法3：range(num1,num2,step)
# for x  in range(2,10,2):
#     print(x)

# for循环，判断1-100有几个偶数
count = 0
for x in range(1,100):
    if x % 2 ==0:
        count += 1
print(f"1到100之间（不包含100），有{count}个偶数")